How to Insulate a Metal Roof

How to insulate a metal roof

Metal roofing sheets are a popular and widely used roofing material in the United Kingdom. Their strong construction and resilient strength make them the ideal choice for heavy-duty structures, providing maximum stability and weatherproofing. Cost-effective, simple-to-install, and low-maintenance, metal roofs are suitable for a wide range of building constructions.

Do Metal Roofs Provide Good Insulation?

Metal roofing has numerous practical benefits, but despite this, the thermal insulative qualities of metal roofing are far less effective than roofing made out of other materials.

If you want to keep the building below your roofing at a stable and comfortable temperature, whatever the time of year, you should really invest in some highly effective insulation to increase the efficacy of your metal roofing.

This article will look at why you should insulate your metal roof, the benefits of insulating it, the most common types of metal roof insulation, and a step-by-step guide on how to install your metal roof insulation.

Environmental Effects of Metal Roof Insulation

It goes without saying that for any roof, no matter what it is made of, the colder the building below, the more energy is required to heat it.

You can considerably lower energy requirements and therefore heating bills with effective insulation. This will also lower the amount of air pollution you are producing and also lower your emissions and carbon footprint. In turn, this will result in a less detrimental impact your property has on the environment.

Cost Savings

When a roof structure is left uninsulated a large quantity of heat and energy is lost. This not only has a negative effect on the environment, but it can also have a significant impact on the amount of money required to be spent on energy bills each year.

You can dramatically reduce the amount of money you spend on energy bills each year, and therefore improve your energy efficiency, with the appropriate use of high-quality insulation. The cost of the insulation could realistically be paid off in just a few years.

Increase in Value

Remarkably, just by adding insulation to a roof structure, you can significantly increase the value of your building. The more energy efficient a building is, the greater the “value rating”. Potential buyers will be more interested in a property that has lower operating costs, while providing a higher level of comfort and more consistent temperature.

Absorption of Sound

Windy weather, heavy rain and hailstones are par for the course when it comes to weather in the UK and as such, structures with built up metal roofs can, as you can imagine, be pretty noisy.

Insulating your metal roof can not only help with thermal insulation, but can also help with sound absorption, noise transfer and even acoustic performance. This would make for a much more relaxed and quieter environment in the structure below.

Increased Comfort

When you insulate your metal roof this will help regulate the temperature in the building below, making it much more comfortable. In hot weather, a metal roof can become quite hot, making the area below unbearable at times.

Adding insulation to your metal roof can not only help reduce heat loss and keep the structure below warmer in the colder months, but it can even help to make it cooler in the summer months.

Improved Protection

Metal roofs are generally highly durable and can generally last up to 40 years. They are effectively fireproof, so a good option in areas where fire might be a concern. By adding an extra layer of insulation to your roofnsu can effectively act as vapour barrier and boost the endurance and thermal protection of your metal roof.

In an uninsulated building with a metal roof, the heat could, in winter, melt snow and ice causing excessive moisture, condensation and ice dams, all of which could cause damage to your metal roof structure.

What Are My Insulation Options?

When it comes to insulating a metal roof, you have a few different alternatives. Each has its own set of benefits and features that make it best suited to certain objectives. The following are some of the most commonly used insulating materials for buildings that have a metal roof:What are my options for metal roof insulation?

Rigid Foam Insulation

Spray Foam

Spray foam is an extremely versatile insulator that may be used in a number of key areas including the loft, roof, walls, and floor. It is a liquid foam that is carefully sprayed into the intended location with specialist high-pressure spray equipment. Once sprayed, the foam expands, and then in minutes, as it reacts with the air, the spray foam hardens, providing a thick, hard and strong foam coating.

Spray foam insulation makes the process significantly faster and easier. It is completely self-adhering, making it ideal for the irregular shapes that can sometimes be found with metal or corrugated roofs.

Fitting into tiny gaps and crevices, spray foam insulation added to the underside completely seals out water and air after swelling and drying, considerably reducing the risks of condensation and moisture damage. This snug fit also helps keeps pollen, allergens, insects, pests, and tiny rodents out.

In addition to being an excellent thermal insulator, spray foam is also excellent for sound absorption and can help to reduce and filter out noise. This is ideal if your building or structure is on a busy commercial industrial estate or in a densely populated residential area.

Fibreglass Insulation

Fibreglass insulation usually comes in rolls or batts and is one of the cheaper options when it comes to metal roofing insulation. Both the rolls and batts are highly practical and are ideal for challenging metal roof shapes, as they can simply be cut to size to accommodate the size and shape of your metal roof structure.

Fibreglass insulation is constructed of tiny, threadlike glass structures that are woven together and combined with a number of other materials to create a thick, robust insulating cushion.

Fibreglass insulation is usually composed of recycled glass, which has major environmental benefits. The structure is strong and tough, and will not collapse quickly, it is also fire resistant, which boosts the safety aspect of any building.

In terms of insulative efficiency, fibreglass insulation is extremely helpful in improving the energy efficiency of your building. The material’s structure traps pockets of air, delaying the passage of both cold and heat, keeping the building cool in the summer and warm in the winter. In addition to thermal insulation, fibreglass helps to minimise noise, resulting in a more comfortable environment.

Although the installation process for fibreglass insulation is straightforward it can be deadly in the hands of someone who is inexperienced and hasn’t used it before. Because the fibreglass contains tiny glass shards, you must always use appropriate PPE during installation, such as gloves, goggles, and a dust mask.

How to Install Metal Roof Insulation on an Existing Structure

Examine the Underside

When you are investigating the underside of any existing building or structure, look for plywood horizontal beams and joists.  Joists are angled beams that are much larger than horizontal beams.

Fill any Gaps with Fibreglass Insulation Batts

To begin insulating the existing structure, insert fibreglass batts between the horizontal beams and the roof decking. Avoid fitting the fibreglass too tightly as this may affect the material’s performance. It is more beneficial to fit as loosely as possible into the gaps.

Rigid Foam Insulation

Then, to offer a broader span of covering for the roof decking between the joists, use rigid foam insulation. Cut the pieces to size with a Stanley knife and then attach them in place with the appropriate adhesive.

It is recommended that you do not use nails or screws since these forms of fasteners can pierce the metal roof sheets and cause leaks.

How to Install a Metal Roof and Insulation on a New Structure

Set up the Roof Decking

It is advised that you use chipboard or plywood boards to build the structural roof decking. Install the plywood or chipboard vertically to the joists, then secure it with galvanised or stainless steel roofing nails.

Install Roofing Membrane

To reduce the possibility of moisture damage and leaks, install a layer of roofing membrane over the decking. Nails or staples can be used to securely fasten the roofing membrane.

Rigid Foam for Protection

Install rigid foam insulation sheets across the entire roof surface above the membrane. Make sure the insulating sheets are butted together but not overlapping.

Beams Must be Sealed

Seal the beams in between the stiff foam insulation sheets using thick duct tape. This will help to reduce moisture, prevent air leaks, and improve the structural stability and strength of the roof.

Put up the Metal Roofing Sheets.

Now that the insulation is in place, you may install the metal roofing sheets on top. Make careful to follow the manufacturer’s directions exactly.

Spray Foam Installation

It is recommended that you acquire a ready-to-install spray foam insulation kit if you are doing your own spray foam installation. A sprayer and closed-cell liquid foam should be included. If you are unsure if your kit is suitable for use, always seek professional guidance before using it.

Make a Hole

To begin, you must first make a small hole in the ceiling. This will make access to the roof framing much easier. If you are unsure about the size of the hole, consult the manufacturer’s installation guide, which should be included with your spray foam kit. This should tell you the correct size of the hole needed and the best place to make the hole for ease of application and installation.

Check the Structure Again

Before spraying, always ensure that the metal roof is supported properly by plywood or chipboard. If you discover that your metal roof does not have these in place then it is recommended that you do NOT attempt to install the spray foam yourself.

This is due to the possibility of the foam moving through the roof joints and causing significant structural damage to both the roof and the building below.

We always recommend that you seek professional advice if you are looking to insulate your metal roof.  If you make a mistake then it could prove to be extremely costly to fix.

Fill the Hole with Spray Foam Insulation

If you are happy that your metal roof has chipboard or plywood beneath it after checking it, you can begin the installation of the spray foam insulation. The next step is to fill the roof cavity via the hole you made previously, with the spray the foam insulation, ensuring you strictly adhere to the manufacturer’s instructions and guidelines.

After being sprayed, the foam will begin to expand and fill the roof structure. Patch up the hole once it has fully expanded, hardened, and cured.

Metal Roof Insulation Summary

Metal roof sheets are a common choice for a variety of architectural constructions around the UK, both in a commercial and residential setting. They are a very effective roofing solution that is ideal for a DIY project due to their practicality and strength, as well as their distinctive visual appeal and versatility.

Choosing and installing the appropriate insulation will help in maximising and improving on this already high-quality and highly effective roofing material, and will, in turn, help you to keep your energy bills much lower.

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